CODEWITHSUNDEEP
androidandroid-jetpack-composeandroid-canvasandroid-jetpack
deadLock
deadLock

Reputation: 104

drawArc() `s working in DrawScope in jetpack compose?

Actually i am reading this article . I am so confuse about the working of startAngle , and direction of arc in drawArc() , can anyone explain this ?

I have read many answers in jetpack compose . i have wasted about 2 to 3 hours to try to understand this function .

In below code why half circle is on left side . as both angles are positive so it should be on right side ?

Preview(showBackground = true)
@Composable
fun PreviewAnimatedRectComposable() {
   GooglePhotosIcon()
}




@Composable
private fun GooglePhotosIcon() {
   Canvas(
       modifier = Modifier
           .size(100.dp)
           .padding(16.dp)
           .border(1.dp , Color.Magenta)
   ) {
       drawArc(
           color = Color(0xFFf04231),
           startAngle = 270f,
           sweepAngle = 180f,
           useCenter = true,
           size = Size(size.width * .50f, size.height * .50f),
           topLeft = Offset(size.width * .25f, 0f)
       )
   }
}

Upvotes: 2

Views: 142

Answers (1)

deadLock
deadLock

Reputation: 104

Actually i get diagram random from google image

image

So in android y axis is opposite that of the cartesian coordinate system . Means The negative y-axis is above the origin, while the positive y-axis is below it.

so StartAngle : indicate starting position of arc sweepAngle : indicate extent of arc If any those angle is negative then direction of arc is anticlockwise otherwise clockwise . From startAngle we decide where arc go either clockwise or anticlockwise depending upon either startAngle or sweepAngle is positive or negative .

So in my code start angle is on top of circle and so all angle are positive so it draw arc in clockwise direction .

Upvotes: 1

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